Christie\'s and Sotheby\'s hold their big autumn art sales in New York starting this week, with both houses looking to Pablo Picasso to excite a robust market. The prominence of important works by Picasso, Matisse and other modern masters in the impressionist and modern art sales at Christie\'s on Tuesday and Sotheby\'s on Wednesday reflects the healthy appetite this year for big-ticket works, auctioneers said. A strong market is also expected the following week when the two houses hold their contemporary art auctions. Simon Shaw, head of the modern and impressionist department at Sotheby\'s, said the offerings are \"slightly bigger in the number of lots, (which) reflects perhaps an increased confidence.\" A low estimate of $185 million is expected for the Wednesday sale, led by Picasso\'s playful and erotic \"L\'Aubade,\" estimated at $18-25 million, and Henri Matissse\'s monumental bronze sculpture of a woman seen from the back, \"Nu de dos,\" estimated at $20-30 million. Another keenly awaited lot is the mosaic-like pastoral scene \"Litzlberg on the Attersee\" by Gustav Klimt, estimated in excess of $25 million. Christie\'s, meanwhile, promised \"a blockbuster\" sale aiming for more than $215 million, with a centerpiece in Edgar Degas\'s landmark sculpture \"Petite danseuse de quatorze ans,\" estimated at $25-35 million. Other star lots include a pair of Picasso portraits from the 1930s, \"Femme endormie\" and \"Tete de femme au chapeau mauve.\" Both are estimated to sell at $12-18 million. \"Picasso remains the gold standard for collectors the world over, and Christies has sold four Picasso works for over the $15 million mark so far this year,\" the auction house said. Sotheby\'s \"L\'Aubade\" is a strong example of Picasso\'s later work, executed in the 1960s when he was in his 80s and fearfully facing the end of his life. \"Picasso had this terrible fear of death, so for him, staying alive was painting or having sex,\" said David Norman, worldwide chairman of the impressionist department at Sotheby\'s. The large work goes in both those directions, depicting a would-be younger Picasso waking his nude lover with a flute in what Norman called an \"ecstatic, blissful, Arcadian state.\" The huge Matisse bas-relief bronze comes with its own tale. It is in fact one of a group of four, with the others named \"Dos II,\" \"Dos III,\" and \"Dos IV.\" Consigned by The Burnett Foundation of Forth Worth, Texas, the group had been on offer for private sale. But although \"there was tremendous interest,\" the package was simply beyond what the market could offer, Norman said. So each of the sculptures will be auctioned independently this year, starting with next week\'s auction. In the current market, \"$20-30 million is considered accessible,\" Norman said. For the contemporary sales, the rival auction houses are taking different tacks. Sotheby\'s \"sale is not focused on pop art,\" said Tobias Meyer, the worldwide head of the contemporary department. Instead, the offerings are strong on painting and color, with Clyfford Still, Gerhard Richter, Francis Bacon and Mark Rothko leading. At Christie\'s, though, pop art will star, with Roy Lichtenstein\'s \"I Can See the Whole Room -- and There\'s Nobody in It!\" and Andy Warhol\'s \"Silver Liz\" and \"Four Campbell\'s Soup Cans.\"